This invention pertains to surgical systems and, more particularly, methods and apparatus for attaching tissue to bone. The invention has application in, for example, rotator cuff repair.
It is not uncommon for tendons and other soft tissues to tear or to detach from bone. Athletes, for example, often suffer "rotator cuff" tears, in which the supraspinatus tendon separates from the humerus, causing pain and loss of ability to elevate and externally rotate the arm. Complete separation can occur if the shoulder is subjected to gross trauma. Typically, however, the tear begins as a small lesion, especially, in older patients.
To repair a torn rotator cuff, surgeons must reattach the supraspinatus tendon to the humerus. Traditionally, this has been done by boring several holes obliquely through the greater tuberosity, that is, the bony structure on the outer side of the head of the humerus. Sutures are then passed through these holes, or transosseous tunnels, in order to secure the tendon.
Though use of such sutures to anchor the tendon have been referred to as the "gold standard," it has been shown that the sutures migrate through the bone itself, particularly, along the upper edge of the openings that define the ends of transosseous tunnels on lateral cortex of the greater tuberosity. This is particularly pronounced in older patients, whose bone structures tend to be weaker and, therefore, less resistant to degradation under the force of the sutures. On prior art solution has been to augment the edges of the transosseous tunnels by affixing plate-like pieces; see, Gerber et al, "Mechanical Strength of Repairs of the Rotator Cuff," Journal of Bone Joint Surgery, v. 76, n. 3, p. 371-380 (May 1994). See France et al, "Biomechanical Evaluation of Rotator Cuff Fixation Methods," The American Journal of Sports Medicine. v. 17. n. 2. pp. 176 et seq.
Drawbacks of plate-like augmentation of the greater tuberosity are the difficulties in positioning and affixing the plates. Though endoscopic surgery is generally preferred, use of augmentation plates necessitates that rotator cuff repair be performed by open surgery. Moreover, the plates must be affixed to the bone by surgical glues in order to avoid risk that they will migrate from the site in the event of suture breakage.
An object of this invention is to provide improved surgical systems and, more particularly, methods and apparatus for attaching tissue to bone.
Another object of this invention is to provide improved methods and apparatus for rotator cuff repair.
A related object of the invention is to provide improved methods for reinforcing the edges of transosseous tunnels against force of sutures.